Potato is one of the staple food crops in North China.  However, potato production in this region is threatened by the low amount and high spatial-temporal variation of precipitation.  Increasing yield and water use efficiency (WUE) of potato by various water management practices under water resource limitation is of great importance for ensuring food security in China.  However, the contributions of different water management practices to yield and WUE of potato have been rarely investigated across North China’s potato planting region.  Based on meta-analysis of field experiments from the literature and model simulation, this study quantified the potential yields of potatoes without water and fertilizer limitation, and yield under irrigated and rainfed conditions, and the corresponding WUEs across four potato planting regions including the Da Hinggan Mountains (DH), the Foothills of Yanshan hilly (YH), the North foot of the Yinshan Mountains (YM), and the Loess Plateau (LP) in North China.  Simulated average potential potato tuber dry weight yield by the APSIM-Potato Model was 12.4 t ha^–1 for the YH region, 11.4 t ha^–1 for the YM region, 11.2 t ha^–1 for the DH region, and 10.7 t ha^–1 for the LP region, respectively.  Observed rainfed potato tuber dry weight yield accounted for 61, 30, 28 and 24% of the potential yield in the DH, YH, YM, and LP regions.  The maximum WUE of 2.2 kg m^–3 in the YH region, 2.1 kg m^–3 in the DH region, 1.9 kg m^–3 in the YM region and 1.9 kg m^–3 in the LP region was achieved under the potential yield level.  Ridge-furrow planting could boost yield by 8–49% and WUE by 2–36% while ridge-furrow planting with film mulching could boost yield by 35–89% and WUE by 7–57% across North China.  Our study demonstrates that there is a large potential to increase yield and WUE simultaneously by combining ridge-furrow planting with film mulching and supplemental irrigation in different potato planting regions with limited water resources.

    Interspecific hybridization is an important approach to improve cultivated peanut varieties. Cytological markers such as tandem repeats will facilitate alien gene introgression in peanut. Telomeric repeats have also been frequently used in chromosome research. Most plant telomeric repeats are (TTTAGGG)_n that are mainly distributed at the chromosome ends, although interstitial telomeric repeats (ITRs) are also commonly identified. In this study, the telomeric repeat was chromosomally localized in 10 Arachis species through sequential GISH (genomic in situ hybridization) and FISH (fluorescence in situ hybridization) combined with 4’,6-diamidino-2-phenylindole (DAPI) staining. Six ITRs were identified such as in the centromeric region of chromosome Bⁱ5 in Arachis ipaënsis, pericentromeric regions of chromosomes A^s5 in A. stenosperma, B^ho7 in A. hoehnei and A^v5 in A. villosa, nucleolar organizer regions of chromosomes A^s3 in A. stenosperma and A^di3 in A. diogoi, subtelomeric regions of chromosomes B^ho9 in A. hoehnei and A^du7 in A. duranensis, and telomeric region of chromosome E^s7 in A. stenophylla. The distributions of the telomeric repeat, 5S rDNA, 45S rDNA and DAPI staining pattern provided not only ways of distinguishing different chromosomes, but also karyotypes with a higher resolution that could be used in evolutionary genome research. The distribution of telomeric repeats, 5S rDNA and 45S rDNA sites in this study, along with inversions detected on the long arms of chromosomes K^b10 and B^ho10, indicated frequent chromosomal rearrangements during evolution of Arachis species.

Peanut kernels rich in oil, particularly those with oleic acid as their primary fatty acid, are sought after by consumers, the food industry, and farmers due to their superior nutritional content, extended shelf life, and health benefits.  The oil content and fatty acid composition are governed by multiple genetic factors.  Identifying the quantitative trait loci (QTL) related to these attributes would facilitate marker-assisted selection or genomic selection, thus enhancing the quality-focused peanut breeding program.  For this purpose, we developed a population of 521 recombinant inbred lines (RIL) and tested their kernel quality traits across five different environments. We identified two major and stable QTLs for oil content (qOCAh12.1 and qOCAh16.1).  The markers linked to these QTLs were designed by competitive allele-specific PCR (KASP) and were subsequently validated.  Moreover, we found that the superior haplotype of oil content in the qOCAh16.1 region was conserved within the PI germplasm cluster, as evidenced by a diverse peanut accession panel.  In addition, we determined that qAh09 and qAh19.1, which harbor the key gene encoding fatty acid desaturase 2 (FAD2), influence all seven fatty acids, including palmitic, stearic, oleic, linoleic, arachidic, gadoleic, and behenic acids.  As for protein content and the long-chain saturated fatty acid behenic acid, qAh07 emerged as the major and stable QTLs, accounting for over 10% of the phenotypic variation explained (PVE).  These findings would enhance marker-assisted selection in peanut breeding, aiming to improve oil content, and deepen our understanding of the genetic mechanisms that shape fatty acid composition.